:root {
      --brand: #00BCFF;
      --brand-glow: rgba(0,188,255,0.18);
      --brand-dark: #0096cc;
      --ink: #0f172a;
      --muted: #64748b;
      --surface: #f0f6ff;
      --card: #ffffff;
      --border: #dde8f5;
      --radius: 18px;
    }

    [data-theme="dark"] {
      --ink: #e2eaf5;
      --muted: #94a3b8;
      --surface: #0d1526;
      --card: #152038;
      --border: #1e3358;
    }

    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

    html { scroll-behavior: smooth; }

    body {
      font-family: 'Sora', sans-serif;
      background: var(--surface);
      color: var(--ink);
      min-height: 100vh;
      transition: background .3s, color .3s;
    }

    /* ── Noise texture overlay ── */
    body::before {
      content: '';
      position: fixed; inset: 0;
      background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.025'/%3E%3C/svg%3E");
      pointer-events: none; z-index: 0;
    }

    /* ── Navbar ── */
    .navbar-custom {
      position: sticky; top: 0; z-index: 100;
      display: flex; align-items: center; justify-content: space-between;
      padding: 14px 40px;
      background: rgba(255,255,255,0.82);
      backdrop-filter: blur(16px);
      border-bottom: 1px solid var(--border);
      transition: background .3s;
    }
    [data-theme="dark"] .navbar-custom {
      background: rgba(13,21,38,0.85);
    }
    .logo {
      font-family: 'Playfair Display', serif;
      font-size: 1.55rem;
      font-weight: 900;
      color: var(--ink);
      letter-spacing: -.02em;
    }
    .logo span { color: var(--brand); }

    .theme-btn {
      width: 40px; height: 40px;
      border-radius: 50%;
      border: 1.5px solid var(--border);
      background: var(--card);
      cursor: pointer;
      display: flex; align-items: center; justify-content: center;
      font-size: 1.1rem;
      transition: all .2s;
      color: var(--ink);
    }
    .theme-btn:hover { border-color: var(--brand); background: var(--brand-glow); }

    /* ── Hero ── */
    .hero-section {
      text-align: center;
      padding: 72px 24px 48px;
      position: relative;
    }
    .hero-section::after {
      content: '';
      position: absolute;
      bottom: 0; left: 50%; transform: translateX(-50%);
      width: 480px; height: 1px;
      background: linear-gradient(90deg, transparent, var(--brand), transparent);
    }
    .hero-title {
      font-family: 'Playfair Display', serif;
      font-size: clamp(2.8rem, 7vw, 5rem);
      font-weight: 900;
      line-height: 1.05;
      color: var(--ink);
      margin-bottom: 16px;
    }
    .hero-title .accent {
      color: var(--brand);
      font-style: italic;
    }
    .hero-sub {
      font-size: 1rem;
      color: var(--muted);
      font-weight: 400;
      font-family: 'Hind Siliguri', sans-serif;
    }

    /* ── Search ── */
    .search-section {
      display: flex;
      justify-content: center;
      padding: 32px 24px 0;
    }
    .search-wrap {
      position: relative;
      width: 100%;
      max-width: 560px;
    }
    .search-wrap i.search-icon {
      position: absolute; left: 18px; top: 50%;
      transform: translateY(-50%);
      font-size: 1.2rem; color: var(--muted);
      pointer-events: none;
    }
    #search-input {
      width: 100%;
      padding: 14px 46px 14px 50px;
      border: 2px solid var(--border);
      border-radius: 999px;
      font-family: 'Sora', 'Hind Siliguri', sans-serif;
      font-size: .95rem;
      background: var(--card);
      color: var(--ink);
      box-shadow: 0 8px 32px rgba(0,0,0,.06);
      outline: none;
      transition: border-color .2s, box-shadow .2s;
    }
    #search-input::placeholder { color: var(--muted); }
    #search-input:focus {
      border-color: var(--brand);
      box-shadow: 0 8px 32px var(--brand-glow);
    }
    .search-clear {
      position: absolute; right: 16px; top: 50%;
      transform: translateY(-50%);
      font-size: 1.1rem; color: var(--muted);
      cursor: pointer; transition: color .15s;
    }
    .search-clear:hover { color: #ef4444; }

    /* ── Lessons section ── */
    .lessons-section {
      max-width: 1200px;
      margin: 0 auto;
      padding: 56px 24px 20px;
    }
    .section-title {
      font-family: 'Playfair Display', serif;
      font-size: clamp(1.8rem, 4vw, 2.8rem);
      font-weight: 700;
      text-align: center;
      color: var(--ink);
      margin-bottom: 32px;
    }
    .section-title .accent { color: var(--brand); font-style: italic; }

    #level-container {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 10px;
      margin-bottom: 40px;
    }
    .lesson-btn {
      padding: 9px 22px;
      border-radius: 999px;
      border: 2px solid var(--border);
      background: var(--card);
      color: var(--muted);
      font-family: 'Sora', sans-serif;
      font-size: .82rem;
      font-weight: 600;
      cursor: pointer;
      transition: all .2s;
      letter-spacing: .03em;
    }
    .lesson-btn:hover {
      border-color: var(--brand);
      color: var(--brand);
      background: var(--brand-glow);
      transform: translateY(-2px);
    }
    .lesson-btn.active {
      background: var(--brand);
      border-color: var(--brand);
      color: #fff;
      box-shadow: 0 4px 18px var(--brand-glow);
      transform: translateY(-2px);
    }

    /* ── Spinner ── */
    #loading {
      display: flex;
      justify-content: center;
      padding: 60px 0;
    }
    #loading.hidden { display: none; }
    .spinner-ring {
      width: 52px; height: 52px;
      border: 4px solid var(--border);
      border-top-color: var(--brand);
      border-radius: 50%;
      animation: spin .8s linear infinite;
    }
    @keyframes spin { to { transform: rotate(360deg); } }

    /* ── Word container ── */
    #word-container {
      display: grid;
      grid-template-columns: repeat(auto-fill, minmax(270px, 1fr));
      gap: 20px;
    }
    #word-container.hidden { display: none; }

    /* ── Word card ── */
    .word-card {
      background: var(--card);
      border: 1.5px solid var(--border);
      border-radius: 22px;
      padding: 0;
      position: relative;
      overflow: hidden;
      transition: transform .25s cubic-bezier(.34,1.56,.64,1), box-shadow .25s, border-color .25s;
      animation: cardIn .4s cubic-bezier(.22,1,.36,1) both;
      display: flex;
      flex-direction: column;
    }
    @keyframes cardIn {
      from { opacity: 0; transform: translateY(20px) scale(.97); }
      to   { opacity: 1; transform: none; }
    }
    .word-card:hover {
      transform: translateY(-6px) scale(1.01);
      box-shadow: 0 20px 48px rgba(0,188,255,.12), 0 4px 16px rgba(0,0,0,.07);
      border-color: var(--brand);
    }

    /* Coloured top band with giant ghost letter */
    .card-header {
      position: relative;
      background: linear-gradient(135deg, #00BCFF 0%, #0ea5e9 60%, #38bdf8 100%);
      padding: 22px 22px 18px;
      overflow: hidden;
      min-height: 96px;
      display: flex;
      flex-direction: column;
      justify-content: flex-end;
    }
    [data-theme="dark"] .card-header {
      background: linear-gradient(135deg, #0284c7 0%, #0369a1 100%);
    }
    .card-ghost-letter {
      position: absolute;
      top: -10px; right: -4px;
      font-family: 'Playfair Display', serif;
      font-size: 7rem;
      font-weight: 900;
      color: rgba(255,255,255,0.15);
      line-height: 1;
      pointer-events: none;
      user-select: none;
      letter-spacing: -.05em;
    }
    .card-word {
      font-family: 'Playfair Display', serif;
      font-size: 1.75rem;
      font-weight: 900;
      color: #fff;
      line-height: 1.1;
      position: relative;
      z-index: 1;
      text-shadow: 0 2px 8px rgba(0,0,0,.15);
    }
    .card-phonetic {
      display: inline-flex;
      align-items: center;
      gap: 5px;
      margin-top: 6px;
      background: rgba(255,255,255,0.2);
      border: 1px solid rgba(255,255,255,0.3);
      border-radius: 999px;
      padding: 2px 10px;
      font-size: .72rem;
      color: rgba(255,255,255,0.92);
      font-style: italic;
      width: fit-content;
      position: relative; z-index: 1;
      backdrop-filter: blur(4px);
    }

    /* Card body */
    .card-body {
      padding: 16px 20px 14px;
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    .card-meaning-label {
      font-size: .65rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: .1em;
      color: var(--brand);
    }
    .card-meaning {
      font-family: 'Hind Siliguri', sans-serif;
      font-size: .92rem;
      color: var(--ink);
      line-height: 1.55;
    }

    /* Card footer with action buttons */
    .card-footer {
      display: grid;
      grid-template-columns: 1fr 1fr;
      border-top: 1px solid var(--border);
    }
    .card-action-btn {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      padding: 11px 0;
      background: transparent;
      border: none;
      cursor: pointer;
      font-family: 'Sora', sans-serif;
      font-size: .75rem;
      font-weight: 600;
      color: var(--muted);
      transition: all .18s;
      position: relative;
    }
    .card-action-btn:first-child {
      border-right: 1px solid var(--border);
    }
    .card-action-btn i { font-size: 1rem; }
    .card-action-btn:hover {
      background: var(--brand-glow);
      color: var(--brand);
    }
    .card-action-btn:hover i { transform: scale(1.2); }
    .card-action-btn i { transition: transform .18s; }

    /* ── Empty / default state ── */
    .empty-state {
      grid-column: 1 / -1;
      text-align: center;
      padding: 80px 20px;
    }
    .empty-state i { font-size: 4.5rem; color: var(--border); display: block; margin-bottom: 16px; }
    .empty-state p { color: var(--muted); font-size: 1rem; }
    .empty-state h3 { font-family: 'Playfair Display', serif; font-size: 1.4rem; color: var(--ink); margin-bottom: 8px; }

    /* ── Modal ── */
    .modal-overlay {
      position: fixed; inset: 0; z-index: 200;
      background: rgba(0,0,0,.5);
      backdrop-filter: blur(4px);
      display: flex; align-items: center; justify-content: center;
      padding: 20px;
      opacity: 0; pointer-events: none;
      transition: opacity .25s;
    }
    .modal-overlay.open { opacity: 1; pointer-events: all; }
    .modal-box {
      background: var(--card);
      border-radius: 24px;
      padding: 36px;
      max-width: 480px;
      width: 100%;
      border: 1.5px solid var(--border);
      box-shadow: 0 32px 80px rgba(0,0,0,.2);
      transform: scale(.94);
      transition: transform .25s;
      position: relative;
    }
    .modal-overlay.open .modal-box { transform: scale(1); }

    .modal-close {
      position: absolute; top: 16px; right: 16px;
      width: 34px; height: 34px;
      border-radius: 50%;
      border: 1.5px solid var(--border);
      background: var(--surface);
      display: flex; align-items: center; justify-content: center;
      cursor: pointer; font-size: 1rem; color: var(--muted);
      transition: all .15s;
    }
    .modal-close:hover { background: #fee2e2; color: #ef4444; border-color: #fca5a5; }

    .modal-word {
      font-family: 'Playfair Display', serif;
      font-size: 2rem; font-weight: 900;
      color: var(--ink); margin-bottom: 6px;
    }
    .modal-label {
      font-size: .72rem; font-weight: 700;
      text-transform: uppercase; letter-spacing: .08em;
      color: var(--brand); margin: 16px 0 6px;
    }
    .modal-text {
      font-size: .9rem; color: var(--ink);
      line-height: 1.6;
      font-family: 'Hind Siliguri', sans-serif;
    }
    .synonyms-wrap { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 4px; }
    .syn-chip {
      padding: 4px 14px;
      border-radius: 999px;
      background: var(--brand-glow);
      color: var(--brand-dark);
      font-size: .78rem;
      font-weight: 600;
      border: 1px solid rgba(0,188,255,.25);
    }

    /* ── Footer-ish stats bar ── */
    .stats-bar {
      max-width: 1200px;
      margin: 0 auto 16px;
      padding: 0 24px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      font-size: .8rem;
      color: var(--muted);
    }
    .stats-bar strong { color: var(--ink); }

    /* ── FAQ ── */
    .faq-section {
      max-width: 800px;
      margin: 72px auto 0;
      padding: 0 24px 80px;
    }
    .faq-title {
      font-family: 'Playfair Display', serif;
      font-size: clamp(1.8rem, 4vw, 2.6rem);
      font-weight: 900;
      text-align: center;
      color: var(--ink);
      margin-bottom: 8px;
    }
    .faq-title .accent { color: var(--brand); font-style: italic; }
    .faq-subtitle {
      text-align: center;
      color: var(--muted);
      font-size: .9rem;
      margin-bottom: 40px;
      font-family: 'Hind Siliguri', sans-serif;
    }
    .faq-item {
      border: 1.5px solid var(--border);
      border-radius: 16px;
      background: var(--card);
      margin-bottom: 12px;
      overflow: hidden;
      transition: border-color .2s, box-shadow .2s;
    }
    .faq-item:hover { border-color: var(--brand); box-shadow: 0 4px 20px var(--brand-glow); }
    .faq-item.open { border-color: var(--brand); }
    .faq-question {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 18px 22px;
      cursor: pointer;
      gap: 12px;
      user-select: none;
    }
    .faq-q-text {
      font-weight: 600;
      font-size: .95rem;
      color: var(--ink);
      flex: 1;
    }
    .faq-icon {
      width: 30px; height: 30px;
      border-radius: 50%;
      background: var(--surface);
      border: 1.5px solid var(--border);
      display: flex; align-items: center; justify-content: center;
      flex-shrink: 0;
      font-size: .85rem;
      color: var(--brand);
      transition: transform .3s, background .2s;
    }
    .faq-item.open .faq-icon { transform: rotate(45deg); background: var(--brand); color: #fff; border-color: var(--brand); }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height .35s cubic-bezier(.4,0,.2,1), padding .3s;
      padding: 0 22px;
    }
    .faq-answer-inner {
      padding-bottom: 18px;
      font-size: .88rem;
      color: var(--muted);
      line-height: 1.7;
      font-family: 'Hind Siliguri', sans-serif;
      border-top: 1px dashed var(--border);
      padding-top: 14px;
    }
    .faq-item.open .faq-answer { max-height: 300px; }

    /* ── Footer ── */
    .site-footer {
      background: var(--ink);
      color: rgba(255,255,255,0.65);
      padding: 56px 40px 32px;
      position: relative;
      overflow: hidden;
    }
    [data-theme="dark"] .site-footer { background: #060d1a; }
    .site-footer::before {
      content: '';
      position: absolute; top: 0; left: 0; right: 0; height: 3px;
      background: linear-gradient(90deg, var(--brand), #38bdf8, var(--brand));
    }
    .footer-grid {
      max-width: 1100px;
      margin: 0 auto;
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 48px;
      margin-bottom: 48px;
    }
    .footer-brand-name {
      font-family: 'Playfair Display', serif;
      font-size: 1.6rem;
      font-weight: 900;
      color: #fff;
      margin-bottom: 10px;
    }
    .footer-brand-name span { color: var(--brand); }
    .footer-desc {
      font-size: .83rem;
      line-height: 1.7;
      max-width: 280px;
      font-family: 'Hind Siliguri', sans-serif;
    }
    .footer-social {
      display: flex;
      gap: 10px;
      margin-top: 20px;
    }
    .social-btn {
      width: 36px; height: 36px;
      border-radius: 50%;
      border: 1.5px solid rgba(255,255,255,0.15);
      background: rgba(255,255,255,0.06);
      display: flex; align-items: center; justify-content: center;
      color: rgba(255,255,255,0.6);
      font-size: 1rem;
      cursor: pointer;
      text-decoration: none;
      transition: all .18s;
    }
    .social-btn:hover { background: var(--brand); border-color: var(--brand); color: #fff; transform: translateY(-3px); }
    .footer-col-title {
      font-family: 'Sora', sans-serif;
      font-size: .7rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: .1em;
      color: var(--brand);
      margin-bottom: 16px;
    }
    .footer-links { list-style: none; display: flex; flex-direction: column; gap: 10px; }
    .footer-links a {
      color: rgba(255,255,255,0.55);
      text-decoration: none;
      font-size: .84rem;
      transition: color .15s;
    }
    .footer-links a:hover { color: #fff; }
    .footer-bottom {
      max-width: 1100px;
      margin: 0 auto;
      padding-top: 24px;
      border-top: 1px solid rgba(255,255,255,0.08);
      display: flex;
      align-items: center;
      justify-content: space-between;
      font-size: .78rem;
      color: rgba(255,255,255,0.3);
      flex-wrap: wrap;
      gap: 10px;
    }
    .footer-bottom span { color: var(--brand); }

    /* ── Responsive ── */
    @media (max-width: 720px) {
      .footer-grid { grid-template-columns: 1fr; gap: 32px; }
    }
    @media (max-width: 640px) {
      .navbar-custom { padding: 12px 20px; }
      .lessons-section { padding: 36px 16px 20px; }
      .site-footer { padding: 40px 20px 24px; }
    }